<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script type="text/javascript">
		  var op1=prompt("请输入第一个数：","");
        var op2=prompt("请输入第二个数：","");
        var sign=prompt("请输入运算符号","")
          var result;
        opp1=parseFloat(op1);
        opp2=parseFloat(op2);
			switch (sign){
				
			  case "+":
                result=opp1+opp2;
                break;
            case "-":
                result=opp1-opp2;
                break;
            case "*":
                result=opp1*opp2;
                break;
            default:
                result=opp1/opp2;
			}
			  alert("两数运算结果为："+op1+sign+op2+"="+result);
			
		</script>
	</head>
	<body>
	</body>
</html>
